// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CC_TILES_DECODED_IMAGE_TRACKER_H_
#define CC_TILES_DECODED_IMAGE_TRACKER_H_

#include <utility>
#include <vector>

#include "base/bind.h"
#include "cc/base/cc_export.h"
#include "cc/tiles/image_controller.h"

class SkImage;

namespace cc {

// This class is the main interface for the rest of the system to request
// decodes. It is responsible for keeping the decodes locked for a number of
// frames, specified as |kNumFramesToLock| in the implementation file.
//
// Note that it is safe to replace ImageController's cache without doing
// anything special with this class, since it retains only ids to the decode
// requests. When defunct ids are then used to try and unlock the image, they
// are silently ignored.
class CC_EXPORT DecodedImageTracker {
public:
    DecodedImageTracker();
    ~DecodedImageTracker();

    void QueueImageDecode(sk_sp<const SkImage> image,
        const base::Closure& callback);
    void NotifyFrameFinished();

private:
    friend class TileManager;
    friend class DecodedImageTrackerTest;

    void set_image_controller(ImageController* controller)
    {
        image_controller_ = controller;
    }

    void ImageDecodeFinished(const base::Closure& callback,
        ImageController::ImageDecodeRequestId id);

    ImageController* image_controller_ = nullptr;
    std::vector<std::pair<ImageController::ImageDecodeRequestId, int>>
        locked_images_;

    DISALLOW_COPY_AND_ASSIGN(DecodedImageTracker);
};

} // namespace cc

#endif // CC_TILES_DECODED_IMAGE_TRACKER_H_
